Tank protective oils



ilnited States 3,090,690 TANK PROTECTIVE OILS Knapel F. Schiermeier, Alton, 111., assignor to Shell Oil Company, New York, N.Y., a corporation of Delaware No Drawing. Filed Oct. 21, 1960, Ser. No. 63,959 3 Claims. (Cl. 106-14) The present invention relates to tank protective oils and more particularly to ballast tank protective oils usable for inhibiting corrosion of cargo tanks of aquatic vessels and to a method for cleaning and inhibiting corrosion of cargo tanks. To meet this problem numerous aqueous, emulsion and oil base compositions are on the market, all of them being essentially ineffective as tank corrosion inhibitors 3,090,090 Patented May 21, 1963 ire covered by treatment with an alkali metal base such as sodium hydroxide followed by extraction. These oilsoluble soaps are available as 30% to 70% concentrates in mineral oil.

The fatty acids used in the partial ammoniated form as described, include fatty acids of from 12 to 30, preferably 14 to 18 carbon atoms and may be derived from animal, vegetable or marine sources, such as fatty acids obtained from cotton seed oil, soya bean oil, coconut oil, corn oil, palm oil, lard oil, tallow and pure saturated and unsaturated fatty acids such as palmitic, stearic, oleic or linoleic acids. A particular suitable fatty acid is tallow fatty acid sold by Emery Industries under the trade name of Emery 500 and 531 fatty acids having the following because of their inability to effectively function as cor- 15 properties:

Iodine Max. Color Free Fatty Acid Sap. Titer, C. Value Lovibond Acid (percent Value Value t (Y/R) Oleic) Emery 500 Fatty Acid 32. 2-40. 65-85 35/10 (1") 90-90 179-191 180492 Emery 531 Distilled Animal Fatty Acid. 40. 542. 51-56 35/6 (51/4) 100. 5-103. 5 200206 202-208 rosion protective liquids for reasonable periods of time, or because of their difliculty of handling or high cost of additives as well as many other reasons such as fear of the protective agent acting as a contaminant, difliculty of removal of the protective coating if desired, etc.

Great expense is incurred annually for the upkeep and repair of metal bulkheads, structural members, etc. of ships (which bulkheads and members are usually made of a ferruginous metal, such as steel), which have been severely corroded, and much time and revenue are lost by the necessity for frequently taking ships out of service for overhaul and repair of damages due to such corrosion.

A principal object of the invention is to provide a protective oil for metal surfaces exposed to or in contact with water and corrosive aqueous fluids. Another object of the invention is to provide a ballast tank protective oil composition which is easy to handle, cheap and non-contaminating by nature. Still another object of the invention is to provide a protective oil which would pass the U.S. Government specification MILR-21006 for ships. Another object of the present invention resides in an improved method of cleaning and coating cargo tanks and inhibiting their corrosion. Other objects of the invention will be apparent from the following description.

It has now been discovered that an excellent tank protective oil composition can be provided, which would pass U.S. Government specifications (MI-R-21006ship and amendments I and II thereto) which essentially comprises a particular mineral lubricating oil base containing from about to about 30%, by weight, preferably -20%, by weight, of an oil-soluble alkali metal (sodium or potassium) petroleum sulfonate in the molecular weight range of 350-900, preferably between 450 and 800 and from about 3%, by weight, to about 10%, by weight, preferably between 4% and 6%, by Weight, of a partially ammoniated fatty acid of from 12 to 30, preferably from 14 to 18 carbon atoms.

By a particular mineral lubricating oil base is meant a mineral oil in the viscosity range of from 400 to 800 SUS at 100 F., preferably having a SUS viscosity at 100 F. at from 450 to 600 and a low viscosity index, namely in the range of 10 to 50, preferably between 15 and 48. By partial ammoniated fatty acid is meant that the ammoniation of the fatty acid is so controlled that the ammoniated fatty acid has a total base neutralization numberelectr0metric method [(TBN-E) as determined by the ASTM-D664 method, in the range of from 20 to 50].

The alkali metal petroleum sulfonates are prepared by reacting a mineral oil with concentrated or fuming sulfuric acid to form oil-soluble sulfonic acid which are then re- The partial ammoniation of the fatty acids may be done by any suitable means such as by bubbling ammonia into a suitable fatty acid at a temperature varying from room temperature to 175 F., preferably between and F. In the present case a preferred method of ammoniating a fatty acid such as Emery 500 fatty acid is to bubble ammonia into a fatty acid at about 150 F. until the product has a TBN-E value of from 30 to 45. The partially ammoniated fatty acid is considered to be a mixture of ammonium salt, e.g. ammonium tallowate or oleate, etc. and free fatty acid. Instead of ammonia the fatty acid may be treated with C alkyl amines such as methyl or ethyl amine, so as to produce a mixture of partially neutralized amine salt of the fatty acid and free fatty acid.

The oil which is particularly suited as a protective base is a low viscosity index oil in the range of 10 to 50, preferably 15-48 VI and a viscosity at 100 F. SUS of 450 to 600. Such a low VI oil is a LVI 573 neutral having the following properties (X):

Gr., API 22 Color, NPA 3.5 Pour point, F 5 Flash, F 400 Fire, F 465 Viscosity at 100 F., SUS 513 Viscosity index 48 Broad Preferred Range Range (percent (percent weight) weight) Partial ammoniated fatty acid, e.g. ammoniated tallow fatty acid (TBN-E value 20-50). 310 4-6 Alkali metal petroleum sulfonate, e.g. Na or Kpetroleum sulfonate 1030 5-20 Optimal additives, eg. anti-oxidants, etc 0.0l-2 0.1-2 LVI mineral oil (450-600 SUS at 100 F.) Balance Balance 3 The following examples illustrate compositions of this invention:

EXAMPLE '1 Percent wt.

.Ammom'ated tallow fatty acid [(Emery 500 fatty acid) (25% neutralized)] 5.0 Na petroleum sulfonate 1 20.0 LVI mineral oil (X) Balance 1 Molecular Weight=450-600 of Na petroleum sulfonate in LVI mineral oil (40 VI, 513 SUS 100 F.) Balance EWPLE IV Ammoniated linoleic acid (40% neutralized) 5.0

Na petroleum sulfonate 25.0

LVI mineral oil (X) Balance EXAMPLE V Ammoniated stearic acid (35% neutralized)- 5.0

Na petroleum sulfonate 30.0

LVI mineral oil (X) Balance Composition of the present invention were tested in accordance with the requirements of MIL-'R-2l006 specification and the results are shown in Table I.

Table I Composition Example I (present invention). Example If (present invention) Example IV (present invention). Mineral oil (X) 1% ammoniated Emery 500 fatty acid (25% neutralized) 4% Na petroleum sulfonate Mineral oil (X) 4% glyceryl monooleate 20% Na petroleum sulfonate Mineral oil (X) 5% ammoniated 500 Emery acid (25% neutralized) M ineral oil (X) 20% N a petroleum sul- 0112 P HVI mineral oil (98 VI, 103 SUS 100 F.)

5% ammoniated oleic acid (40% neutralized) Na petroleum suli0nate Mineral oil (X) 5%completely ammoniated (neutralized) 500 Emery acid 20% Na petroleum sulfonate Commercial Ballast Tank Oil Petrotect 2406 (oil base, rust preventive composition made by Penn. Refining Co.) Commercial Ballast Tank Oil Tectyl 884 (corrosion inhibiting composition comprising a petroleum solvent base containing polar organic compounds made by Freedon-Valoline Oil Co.) Mineral oil (X) micro 1 5.0 mils/year, specification limit. I 7.5 mils/year, specification limit. Too unstable for testing. 7

4 Unstable.

The compositions of the present invention can he further improved with respect to oxidation stability by addition thereto of from 0.01% to 2%, preferably from 0.1% to 2% of polymeric ashless dispersants such as nitrogencontaining polymers described in US. Patents 2,737,496, 2,839,512, 2,889,282, 2,944,974 or British Patent 808,665 or polyhydric polymeric compounds described in 'U.S. Patents 2,800,450-2. Polymers of this type having a molecular Weight of from 20,000-800,000 can be illustrated by copolymer of lauryl methacrylate/diethylaminoethyl methacrylate, copolymer of Z-methyl-S-vinylpyridine/ lauryl methacrylate/ stearyl methacrylate, copolymer of 2-rnethy-l-5-vinylpyridine/lauryl methacrylate/stearyl methacrylate/ methyl methacrylate, copolymer of vinyl pyrrolidone/lauryl methacrylate, hydrolyzed copolymer of C1048 alpha-olefin/vin-yl acetate. Also desirable is the presence of small amounts (0.1-1%) of phenolic antioxidants such as mono or bisphenols, preferably phenols which contain at least one tertiary alkyl radical. Alkyl phenols of this type include 2,4,6-triet-hyl-,

tributyl-,

trioctyl-, 2,4-ditert-butyl-6-methyl, 2,6-ditert-butyl-4-methyl, 2,4,6-ditert-butyl-, 2,6-dicyclohexyl-4-methyl, 2,6-dimethyl-4-cyclohexylphenols, 2,6-ditert-butyl,

2,2-ditert-butyl, 2,6-tert-butylcyclohexyl, 2-rnethyl-6-tert-butyl-4-methylphenols.

The alkyl bisphenols include 1,1-bis-(2-hydroxy-3 -tert-butyl-S-rnethylphenyl)methane;

bis 2-hydroXy-3 -tert-butyl-S-rnethylphenyl) ethane;

1, l-bis 2 hydroXy-3 -tert-butyl-S-methylphenyl propane;

bis (2 hydroxy-3 -tert-butyl-5-rmetl1ylpbeny1 butane;

bis (2-hydroXy-3 -tert-butyl-5-methylphenyl) isobutane;

1, l-bis 6 hydroxy-5 -tert-'butyl-3 -methylphenyl methane;

bis 2-hydroxy-5-tert-butyl-3 methylphenyl) ethane;

1 1-bis 2-hydroxy-5-tert-butyl-3 -methylphenyl propane;

1, 1 -bis 2-hydroxy-5-tert-amyl-3 -methylphenyl) butane;

l, l-bis (2-hydroxy-5 -tert-amyl-3 -methylphenyl) isobutane;

etc.

The 2,4,6-trialkyl phenols containing two tertiary alkyl groups in the 2,4- or 2,6-positions are preferred, such as 2,4-diterbbutyl-G-methyl 2,6-ditert-butyl-4-methylphenol or 2,6-ditert-butyl-4-methylolphenol or 4,4-methylene bis (2,6-d-ibutylpheu1ol) Compositions of the present invention may be also used as corrosion inhibitors for various metal surfaces in contact with moisture, corrosive materials and the like.

I claim as my invention:

1. An improved tank protective oil composition consisting essentially of from about 10% to 15% of an oilsoluble alkali metal petroleum sulfonate in the molecular Weight range of from 350 to 900and from about 4% to 6% of a partially ammoniated fatty acid selected from the group consisting of oleic acid and tallow fatty acid having a TBN-E value in the range of about 20 to 50, and the balance being a mineral oil having a viscosity index of from 15 to 48 and a viscosity at F. SUS of from 450 to 600. v

2. An improved tank protective oil composition consisting essentially of from about 15% to 20% of an oil-soluble sodium petroleum sulfonate in the molecular weight range of from 350 to 900 and from about 4% to 6% of a partially ammoniated oleic acid having a TBN-E value in the range of from 20 to 50 and the balance being a mineral oil havinga viscosity index of from 15 to 48 and a viscosity at 100 -F. SUS of from 450 to 600.

3. -An improved tank protective oil composition consisting essentially'of from about 15 to 20% of an oilsoluble sodium petroleum sulfonate in the molecular weight range of from 350 to 900 and from about4% to 6% of a partially ammoniated tallow fatty acid having a 'IBN-E value in the range of from 20 to 50' and the balance. beinga mineral oil having a viscosity index of from 15 to 48 and a viscosity at 100 -F. SUS of from 45 0 to 600.

References Cited in the file of this patent UNITED STATES PATENTS 2,840,477 Shock et a1 June 24, 1958 

1. AN IMPROVED TANK PROTECTIVE OIL COMPOSITION CONSISTING ESSENTIALLY OF FROM ABOUT 10% TO 15% OF AN OILSOLUBLE ALKALI METAL PETROLEUM SULFONATE IN THE MOLECULAR WEIGHT RANGE OF FROM 350 TO 900 AND FROM ABOUT 4% TO 6% OF A PARTIALLY AMMONIATED FATTY ACID SELECTED FROM THE GROUP CONSISTING OF OLEIC ACID AND TALLOW FATTY ACID HAVING A TBN-E VALUE IN THE RANGE OF ABOUT 20 TO 50, AND THE BALANCE BEING A MINERAL OIL HAVING A VISCOSITY INDEX OF FROM 15 TO 48 AND A VISCOSITY AT 100* F. SUS OF FROM 450 TO
 600. 